# INFINITY

From cppreference.com
< c‎ | numeric‎ | math

Defined in header ``<math.h>`` |  |
#define INFINITY /*implementation defined*/ |  | (since C99)

If the implementation supports floating-point infinities, the macro `INFINITY` expands to constant expression of type float which evaluates to positive or unsigned infinity.

If the implementation does not support floating-point infinities, the macro `INFINITY` expands to a positive value that is guaranteed to overflow a float at compile time, and the use of this macro generates a compiler warning.

The style used to print an infinity is implementation defined.

### Example

Show style used to print an infinity and IEEE format.

Run this code

    #include <stdio.h>
    #include <math.h>
    #include <stdint.h>
    #include <inttypes.h>
    #include <string.h>

    int main(void)
    {
        double f = INFINITY;
        uint64_t fn; memcpy(&fn, &f, sizeof f);
        printf("INFINITY:   %f %" PRIx64 "\n", f, fn);
    }

Possible output:

    INFINITY:   inf 7ff0000000000000

### References

- C11 standard (ISO/IEC 9899:2011):

  - 7.12/4 INFINITY (p: 231-232)

- C99 standard (ISO/IEC 9899:1999):

  - 7.12/4 INFINITY (p: 212-213)

### See also

isinf (C99) | checks if the given number is infinite (function macro)
HUGE_VALFHUGE_VALHUGE_VALL (C99)(C99) | indicates value too big to be representable (infinity) by float, double and long double respectively (macro constant)
C++ documentation for INFINITY

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